The function \( f(x)=e^{|x-1|} \) is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → continuous everywhere but not differentiable at \( x=1 \)
Since \( e^{u} \) and \( u=|x-1| \) are both continuous everywhere, their composition f is continuous everywhere. The only doubtful point for differentiability is x = 1, where |x − 1| has a corner.
\( \displaystyle f(x)=\begin{cases}e^{1-x}, & x\lt 1\\e^{x-1}, & x\ge 1\end{cases} \)
\( \displaystyle \text{LHD at }1=\lim_{x\to 1^-}\left(-e^{1-x}\right)=-1 \)
\( \displaystyle \text{RHD at }1=\lim_{x\to 1^+}e^{x-1}=1 \)
The left-hand and right-hand derivatives differ, so f is not differentiable at x = 1. Elsewhere each piece is differentiable.
So f is continuous everywhere but not differentiable at x = 1.